33S JOURNAL OF THE KOYAL HORTICULTURAL SOCIETY. 



Almost all the winter washes were successful in killing American 

 blight, particularly those which had petroleum as one of their ingredients, 

 providing sufficient force was applied to drive the wash into the crevices 

 where the pest had made its abode. 



The same may be said with regard to the mussel scale. It has been 

 largely cleared off the trees ; and again the petroleum compounds seem to 

 have been most successful, which will not surprise many fruit growers, as 

 paraffin has been found long ago to be useful applied with some clay as a 

 paint for this pest. 



Of course, no observation of this, other than microscopic, is of any use 

 in the spring time, as to the results of spraying for mussel scale, for these 

 scales are but the shell of the insect protecting the eggs, and it is only 

 when the eggs hatch out, and new insects grow, that we can tell what 

 good we have done ; and even then we may congratulate ourselves on 

 something we have never accomplished, since the scale has a parasitic 

 enemy which devours the eggs sometimes to the extent of half their 

 number. However, granting all this, looking at sprayed and un sprayed 

 trees in the summer, we can tell easily that much good has been accom- 

 plished. 



Leaving winter spraying, I think we can divide the insects we have to 

 spray for in summer roughly into two classes — those we must kill by direct 

 contact with the spray and those whose food we must poison, and so destroy. 

 Among the former are included the different aphides, apple sucker, and 

 red spider, and the latter comprise all the leaf-eating caterpillars and 

 various beetles. For many years for the former class quassia and soft 

 soap was universally recommended as the wash, and is even now very 

 useful indeed ; but it has been gradually superseded by paraffin emulsified 

 with soft soap. 



The need for emulsifying is, of course, abundantly clear to anyone who 

 thinks of the impossibility of mixing paraffin and water together, and who 

 also thinks of the damage the unmixed drops of paraffin will do to the 

 leaves of the trees. The emulsion is made by churning certain quantities 

 of paraffin and a solution of soft soap by means of a syringe or pump, and 

 then diluting to the required strength. But even when the emulsion is 

 ever so carefully made, on diluting it some of the paraffin is sure to 

 separate. 



This year we have used another emulsion, which has been very much 

 more successful, in which the emulsifying agent has been iron sulphate, 

 with which we never had the slightest trouble to keep the paraffin mixed 

 up. For this, as for many other notable investigations, we are indebted to 

 Mr. Spencer Pickering of Woburn. We found this wash quite successful 

 in killing aphides where it could be got at them, and also red spider, but 

 it was not so good at killing apple sucker, either on the wing or in the 

 bunches of bloom. However, though this is a useful wash it has a draw- 

 back in that it leaves a rust, like a deposit of iron, on the leaves and fruit 

 which might damage the fruit for sale unless soon washed off by heavy 

 rain. 



Though this wash was not fatal to apple sucker another of Mr. 

 Pickering's remedies was absolutely so ; in fact I have no hesitation in 

 saying that wherever it touched any insect it was fatal to it. This was a 



